A number of publications appeared by the authors V. A. Sequin et al. of the Department of Electrical Engineering of the University of Alberta, Edmonton, Alberta, Canada (see Applied Optics, Vol. 25, No. 21, pg. 3825-3829, Nov. 1, 1986 and references) describing a configuration similar to that of the invention but inventively distinct from it. They use a non-homogeneous magnetic field to avoid end effects, produced by the anode itself (anode/solenoid), the cathode being a multi-element hollow button electrode. Both anode and cathode are cooled by a dielectric fluid. The gas discharge is nonself-sustained, magnetically stabilized, photoinitiated, impulseenhanced, electrically excited (MAGPIE) and the CO.sub.2 gas mixture flows through the gain region in a closed cycle with the aid of axial flow fans. The magnetic field is about 83 (Gauss) and its only purpose is to stabilize the electrical gas discharge and increase the power loading to their device. The magnetic field is a weak and non-homogeneous one.